ゲームオブジェクトのローカルのアクティブ状態（読み取り専用）
This returns the local active state of this GameObject, which is set using GameObject.SetActive.
Note that a GameObject may be inactive because a parent is not active, even if this returns true. This
state will then be used once all parents are active. Use
GameObject.activeInHierarchy if you want to check if the GameObject is actually treated as
active in the Scene.
See Also: GameObject.SetActive, GameObject.activeInHierarchy.